In photographic products such as print paper for color prints where the market demands delivery of high volumes of prints in a short period of time, the need to decrease developing time has resulted in the increased use of silver bromide which contains essentially no silver iodide, such as, for example, silver chlorobromide.
In response to recent demands for even more rapid processing of color printing paper, processes have been developed where the silver chloride content of the silver halide emulsion has been increased to produce dramatic improvement in developing time.
The photosensitive materials produced by these processes, however, have exhibited a severe lack of consistency among different lots during the production processes in terms of the photographic properties such as spectral sensitivity due in part to the deterioration of the photosensitive materials. This has posed significant practical problems to the use of these materials. It is clear that severe problems are attendant with the use of these so-called "high silver chloride emulsions".
Improvements in spectral sensitivity, storage properties, and in infrared photographic fog have been reported for methods involving the addition of water-soluble bromides (JP-A No. 52-151026 (the term "JP-A" as used herein refers to an "unexamined published Japanese patent application")), the addition of iridium salts (JP-A No. 54-23520), the addition of hardening agents (U.S. Pat. No. 4,618,570 corresponding to JP-A No. 60-202436 and U.S. Pat. No. 4,670,377 corresponding to JP-A No. 61-123834), the addition of color sensitizing agents (JP-A No. 61-203447) and the addition of spectral sensitizing dyes (U.S. Pat. No. 4,442,201 corresponding to JP-A No. 58-7629).
In addition, JP-A No. 60-225147 proposed the addition of silver chlorobromide having (100) and (111) crystal planes in order to improve spectral sensitivity and storage properties, and to reduce the differences among emulsion lots.
However, none of these methods have proven entirely satisfactory in terms of consistency among manufacturing batches or in terms of storage properties.